Generally, vacuum cleaners generate a suction force to draw-in dust or other contaminants through a suction nozzle. A contaminants collecting apparatus is disposed in a main body of the vacuum cleaner. It separates contaminants from air and collects the contaminants. The term “contaminants” will be used herein to refer collectively to dust, dirt particulates, debris, and other similar matter than can be entrained with the air drawn in by the vacuum cleaner. The air is then discharged outside the main body of the vacuum cleaner.
Conventional contaminant collecting apparatuses use a cyclone separating apparatus to separate contaminants from air by centrifugal force that separates contaminants from air and removes relatively large contaminants from air. However, such conventional apparatuses cannot effectively remove fine contaminants from air.
To remove fine contaminants more effectively, a multi-cyclone separating apparatus has been developed. However, in the conventional multi-cyclone separating apparatus for a vacuum cleaner, air enters and is discharged through an upper portion of the first cyclone. Because the air whirls downward and then whirls upward to exit, the complex air path prevents high contaminant separating efficiency. Also, the contaminants separated from the first cyclone are often collected in a space that is in fluid communication with whirling air. Thus, the collected contaminants impede the whirling of the air and therefore reduce the centrifugal force developed which reduces contaminant separating efficiency.